Dynamically balanced vibrating agitators



July 31, 1956 A. W. DOSTATNI 2 Sheets-Sheet 2 /dZ-J d# '/QQ' Fue. 2.

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3y 3/ FIG. 7. =F F V? *Lk 'l EPI T q l-rTm-- l z -U, @'u: W 757 i@ J "f f F l s a f INVENTOR ALBERT w. DQSTTNI m YM ATTORNEYS y 2,756,973 Patented July 31, 1956 DYNAMICALLY BALAN CED VBRATING AGITATORS Albert Wojciech Dostatn, Saint-Germain-en-Laye, France, assignor to Societe Preparation industrielle des Combustibles, Fontainebleau, France, a French company Application December 8, 1953, Serial No. 396,988

Claims priority, application France December 10, 1952 8 Claims. (Cl. 259-72) This invention relates to vibration driving apparatus for. applying vibrating motion to displaceably mounted bodies, without transmitting severe stresses to the supporting structure.

For various purposes, it is necessary to apply vibrating movement continuously to different structures. For instance, certain kinds of apparatus for treating coal, ore, and the like, such as screens, sieves, oscillating chutes, -and the like, are subjected to vibrating movement applied by vibrating operating members, so that the coal or ore may be suitably treated for sifting or separating various of its components.

In some types of high speed vibration apparatus, there are used eccentrically supported or over-centered weights supported by the element to be vibrated. In another type-of vibration apparatus, there is used a rotatable eccentric carried on a shaft mounted in bearings on pedestals, the element to be vibrated being resiliently supported. In the latter case, the shaft is usuallypositioned a little above the element to be vibrated.

The vibrating movements of the moving parts of such machines are often dynamically unbalanced and give rise to forces of inertia, which forces, or the couples associated therewith, are dicult or impossible to counterbalance by known systems. The frame of the vibrating machine transmits to its supports, oscillating dynamic stresses which are likely to cause vibrations that endanger the whole installation, especially and most frequently when the vibrating machine is placed high in a building that houses several units of this kind. Thus, many apartment houses forbid the operation above the ground floor of washing machines having dynamically unbalanced rotors.

Heretofore, the effort has been made to reduce the application of such dynamic stresses :from vibrating mechanisms, either by the useof shock absorbers iso-- lating the frame of the vibrating machine from the floor, or by reinforcing the construction of the building or structure in order to make it more rigid, or by using suitable counterweights to improve the balancing. All of these means heretofore used present the common disadvantage in that they add to the number of operating elements usually required, other elements not directly contributing to the treatment of the ore or other material, but which other elements increase the weight and initial cost of the machines and the whole installation.

An object of the present invention is to avoid these disadvantages by providing a vibrating machine in which the counterbalancing of the forces of inertia of the principal vibrating elements, and their couples, is effected completely without adding or altering any element other than that or those directly serving to treat the ore or other material.

Another object of the present invention is to provide a dynamically self-balancing vibration apparatus comprising three parts or bodies to be vibrated, base-means whereon the three bodies are mounted in substantially horizontal alignment for substantially rectilinear vibratory movement, reciprocating means for causing each of the bodies to reciprocate, with the two outer ones of the bodies being driven in opposite directions from the third central one of the bodies and with the common center of gravity of the two outer bodies being moved with respect to the center of gravity of the central body in such a manner that the common center of gravity of the system consisting of all of the vibrating bodies remains fixed in position, whereby the forces generated by the movements of the bodies balance each other out.

The general principle of the present invention is as follows: The total mass of the vibrating members of a machine, including the mass of the driving mechanism, if the latter is of the ilo-ating type, is divided into three parts; that is, a central part and `tw'o outside parts. The arrangement of the vibrating members and the kinematic system of the driving velements that drive the vibrating members are determined so that the center of gravity of the central vibrating member and the common center of gravity of the outside vibrating members etect their respective vibrations according to two substantially straight and parallel lines that pass substantially through or as near' a's possible to, the center of gravity common to all the vibrating members, that is, the center of gravity of the system consisting of all of the vibrating members, and so that this common center of gravity of all the vibrating members, does not move, but remains fixed in position.

The invention will be understood from the following specication by reference to the accompanying drawings, wherein:

Fig. l shows diagrammatically in elevation a first embodiment of the invention using a three-body vibrating system in which the vibrating drive system is mounted in iloating relation to the hase, according to the invention;

Fig. 2 shows a diagram of the forces acting, and the locations of the centers of gravity, of the elements of the apparatus of Fig. l;

Fig. 3 is a diagram of the successive positions of the elastic line of the frame of the apparatus lof Fig. l;

Fig. 4 shows in elevation a detail of the eccentrics and connecting rods-of the embodiment ot' Fig. l;

'Fig 5 shows diagrammatically in elevation another modied embodiment of the invention, of a three-body vibrating system in which the vibrating drive system is mounted xedly with reference to the base, according to the invention;

Fig. 6 is a plan view of a detail of\the eccentrics and connecting rods of Fig. 4, with parts in section;

Fig. 7 is a plan view of the modication of Fig. 5, and

Fig. 8, is a vertical section on the line 8 8 of Fig. 5, through the crank shaft ofthe fixed driving mechanism. Y

Referring to Fig. 1, the three bodies 1, 2, 4 of the screen vibrating system,rest on the frame 5, which to a certain extent inherently has elastic properties, through the intermediary of the flexible blades 6 which are inclined at an angle Q selected as suitable for the kind of service for which the machine is intended, and also through the intermediary of the bearing springs 7. Bodies 1, 2, 4 are mounted for reciprocating displacement in planes which are substantially parallel.v

The floating Vibrating drive mechanism 3 which is directly mounted on the central body 2 by means of supports 13, 13 (Fig. 4), is connected with the outside bodies 1 and 4 through connecting rods 8 and 9. Float- ,ing drive mechanism 3 comprises a shaft 14 (Fig. 4)

a driving pulley.l 10, and two connecting-rod heads 16, the latter being mounted on the eccentrics 1S, 15, with roller bearings 17, 17. The roller bearings 17, 17, are held in head 16 by cover members 17b. The roller bearings 17a, 17u, are held in supports 13, 13, by cover members 13a.

Each connecting-rod 8 or 9 comprises four flexible blades 18., 18, 18, 13 (Fig. 4), similar to supporting blades 6.

The mass of each outer body 1 or 4 (m1 or m4), equals half the mass (1112.3) of the central body 2, including the mass of the drive mechanism, as shown in Fig. 2, which relation may be written The mean locations of the centers of gravity of the outside bodies 1 and 4, shown at G1 and G4 in Fig. l, are` positioned symmetrically with respect to the mean location of the center of gravity G2.3 of the central body 2 (Fig. l). The center of gravity of the system consistingA of all the three vibrating bodies 1, 2, 4, is shown at G in Fig. 2. The whole arrangement through frame 5 rests on two sills 11 and 12 which, in turn, rest on a base structure I.

The three vibrating members 1, 2, 4 are so arranged that the center of gravity of the central vibrating member 2 and the common center of gravity of the outside members 1 and 4 eiect their respective vibrations in their respective planes according to two substantially straight and parallel lines passing substantially through or as near as possible to the center of gravity G common to all the three members 1, 2, 4; that is, thc center of gravity of the system consisting of all the vibrating members, and so that this common center of gravity G remains xed in position. In other words, the common center of gravity of the two outside members 1 and 4 is moved with respect to the center of gravity of the central vibrating member 2 in such a manner that the common center of gravity G of the three members 1, 2 and 4 remains fixed in position.

The system of Figs. l-4 operates as follows:

The shaft 14 drives, by means of its eccentrics 15, 15, the connecting rods 8 and 9, and thereby imparts to the outside bodies 1 and 4 and to the central body 2, opposed, parallel and linear vibrations of equal amplitude. The locations of the axes of vibration a1 and a4 of the outside bodies (Fig. 2) are symmetrical with reference to the axis of vibration 012.3 of the central body 2.

The end positions of the masses and the centers of gravity of the three bodies 1, 2, 4, respectively, are shown in Fig. 2 by the hatched and blank circles s1, s2.3, s4, t1, t2;3, t4. The three forces of inertia, F1, F2.3, F4 (Fig. 2), and their equal and opposed couples are transmitted to the supporting frame 5 and balance in it.

The successive deflections of the supporting frame 5 cause its elastic line to vibrate about its rest position O- O (shown in dot-dash line) as shown in Fig. 3, to the extreme positions shown in full line and in dotted line.

`Since the sills 11 and 12 are located under the nodal points N11 and N12 (Fig. 3) of the elastic line of frame 5, any dynamic reaction of the vibrating system on to the supporting structure is eliminated, whatever may be the dynamic deection of the frame 5, and the frame 5 vibrates without restraint.

Fig. 5 shows another modified embodiment of the screen vibrating system according to the invention, which differs from the first embodiment of Fig. rl, in that it is driven by means of a drive mechanism D which is fixed in position, instead of the floating drive mechanism 3 of Fig. 1. The central and outside bodies 19, 20, 21, of Fig. 5, rest on the frame 22 by means of parallel, exible blades 23. The mechanism running in the bearings 24, 24, includes a crank shaft 25 with four identical eccentrics 35, 36, 37, 38 (Fig. 8) mounted in usual manner, a

driving pulley 26, and four connecting-rod heads 27, 27, 27, 27. The bearings 24, 24 are xedly mounted on a fixed abutment A. The two inside connecting-rods 28, 28 are directly connected on to the central body 20 and their plane passes through the center of gravity of the latter.

The two outside connecting-rods 29, 29 are connected with outside bodies 19 and 21 by means of two connecting bars, 30, 30, and their plane passes through the center of gravity which is common to the outside bodies 19l and 21. The angle B between the two planes of the two connecting-rods is very small or even equal to zero. The heads 31, 31, connecting the outside connecting rods 29, 29 with the connecting bars 30, 30 are supported on frame 22 through the intermediary of exible blades 32. The masses of the outside bodies 19 and 21 are respectively equal to half the mass of the central body 20, and the system is so arranged that the mean positions of their centers of gravity 40, 41 are symmetrical with reference to the mean position of the center of gravity of central body 20.

The whole driving vibrating arrangement is supported through frame 22 on sills 33 and 34 placed under the vibration nodal points of frame 22, these sills 33 and 34 resting on a base structure K.

The operation of the vibrating system of Fig. 5, is similar to that of the embodiment shown in Fig. l. Through the connecting rods 28 and 29, and the connecting bars 30, 30, the drive mechanism imparts to the outside bodies 19 and 21, and to the central body 20, opposed, parallel, and linear vibrations, of equal amplitude. The forces of inertia of the bodies 19, 20, 21, are constantly balanced, and their couples are in balance within the supporting frame 22, in the same way as in the embodiment of Fig. l. The sills 33 and 34 cannot, therefore, be submitted to the application of any dynamic reaction from the vibrating system, and frame 22 vibrates without restraint.

To those skilled in the art it will be apparent that modilications may be made in the system of my invention without departing from the scope of my invention.

Thus, for the dynamic balancing of such a system, it may be useful to take into consideration the couples of secondary forces of inertia resulting from the eccentric drive of connecting rods 3 and 9 (Fig. l), with respect to the centers of gravity (G1, G2.3., G4) of the bodies 1, 2, 4. In order to balance these secondary couples, it is suticient to align the centers of gravity G1, G2.3, and G4 (Fig. l) on the one hand and the axes of the connecting rods S and 9 (Fig. l) on the other. It is also possible to prevent the formation of these couples by having the plane of the connecting rods 8 and 9 pass through the three centers of gravity G1, G2.3 and G4 (Fig. 1). The axis of the mechanism would then p ass through the center of gravity G2.3 of the central body 2.

Either the central body, or one or both of the outside bodies, or all three bodies, may be made of several individual smaller elements, or they may, if necessary, comprise one or more counterweights.

What is claimed is:

l. In a dynamically self-balancing vibration unit, three bodies to be vibrated, base means whereon said bodies are mounted in substantially horizontal alignment for substantially rectilinear vibratory movement, reciprocating means for causing each of said bodies to reciprocate with the two outer ones of said bodies being driven in opposite directions from the third central one of said bodies, the common center of gravity of the two outer bodies being moved with respect to the center of gravity of the central body in such a manner that the common center of gravity of the entire system consisting of all the said bodies remains fixed in position.

2. A unit according to claim 1, the mass of each said outer body being substantially one-half ofthe mass of said central body.

3. A unit according to claim 1, said bodies being so constructed and arranged that during operation, the mean positions o-f the centers of gravity of the outer ones of said bodies are symmetrical with respect to the mean position of the center of gravity of the said central body.

4. A unit according to claim 1, said reciprocating means being mounted in oating relation to said base means.

5. A unit according to claim 1, said reciprocating means being mounted in fixed relation to said base means.

6. A unit according to claim 1, said base means comprising a frame member, flexible blades connecting each said body to said frame member, and a pair of sills positioned under said frame member at nodal points thereof for unrestrainedly supporting the same during 0peration.

7. A unit according to claim 1, wherein said reciprocating means comprise a driven shaft, a plurality of eccentrics mounted on said shaft, support means directly mounted on said central body for rotatably journaling said shaft, and means including eccentrics mounted on said shaft and connecting rods for connecting said two outer bodies to be driven by said shaft.

8. A unit according to claim 1, wherein said recprocating means comprises a driven shaft mounted in fixed relation to said base means, a plurality of eccentrics mounted on said shaft and a. plurality of connecting rods extending from said eccentrics with at least one of said connecting rods being connected to drive said central body and at least one of said connecting rods being connected to drive the two outer of said bodies and wherein said bodies and the connecting rods connected thereto are so arranged that the vibrations of the bodies are in the direction of the axis of said connecting rods.

References Cited in the le of this patent UNITED STATES PATENTS 436,476 Hatch Sept. 16, 1890 770,401 Thomassen Sept. 20, 1904 807,475 Le Bosquet et al Dec. 19, 1905 814,196 Forsythe Mar. 6, 1906 1,381,780 Brass Apr. 20, 1926 

